354 



M. Haidinger on the Phenomena attending 



fall to the surface of the earth, with a velocity probably inferior 

 to that of a bullet shot from a gun, the air increasing in density 

 as it becomes nearer the surface of the globe, resistance in- 

 creasing proportionally, so that there may be but a slight differ- 

 ence in the final velocity, whether the body fall from a height of 

 one or of five miles." 



I have here quoted views somewhat opposed to those which I 

 myself intend to propose (as those relating to the explanation of 

 the explosion of fireballs) ; yet some of the above-quoted assertions 

 may perhaps be worth further consideration. 



The following exposition of the way in which this may occur 

 may not be altogether devoid of probability. Compression, first 

 of all, developes heat and light. Immediately in front of the 

 meteorite is formed a centre of expansion, from which the com- 

 pressed air tends to expand in every direction. Whatever lies 

 in the direction of the orbit, is left in the rear of the progressing 

 meteorite ; whatever lies opposite to it, contributes to the fusion 

 of the superficial crust, or by its resistance either retards its 

 progress, or gives rise to a rotatory movement around an axis 

 coinciding with the meteorite's orbit, even if it should have un- 

 dergone such a motion only on entering the terrestrial orbit. A 

 part of the air made luminous by compression, is forced out as 

 at C, in every direction perpendicularly to the orbit AB (fig. 1). 

 Resistance continues against this luminous disc, forces it back- 

 wards, overcomes it 

 gradually at some 

 distance from the 

 centre towards EE', 

 and rounds it off 

 behind the meteor- 

 ite in the sTiape of 

 an igneous globe, 

 either round, or as 

 frequently happens 

 oviform; occasion- 

 ally extended so far 

 back as to form 

 even an actual tail. 



Instances of two or more luminous bodies behind each other 

 have been observed, as those seen at Elmira, Long Island, United 

 States, July 20, 1860 ; at Littau in Moravia, end of August 1848 

 or 1849; at Collioure in France, February 21st, 1846. In 

 these cases we may suppose that the single fireball first seen 

 contained already a certain number of fragments, acted upon 

 differently by the resistance of the air, according to their differ- 

 ences in size, shape, and perhaps specific gravity, so that the 



